Transformer relay



Nov. 19, 1940. A JUDSON 2,221,973

TRANSFORMER RELAY Original Filed Dec. 1932 PRIMARY WINDING 3a 26 Fig. l T

' l8 SECONDARY wnNmNe Fig. 2

INVENTOR .Alberi L. Judson ATTORNEY Patented Nov. 19, 1940 UNITED STATES PATENT OFFICE TRAN SFQRMER RELAY Albert L. Judson, Minneapolis, Minn, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware 2 Claims.

This application is a division of my prior application, Serial No. 646,080, filed Dec. '7, 1932, for Burner control apparatus, which became Patent No. 2,075,289 on March 30, 1937. The present application is directed to the new and novel transformer relay shown and described in the prior application.

An object of the present invention is to provide a transformer relay of simple compact form which is particularly free from vibration arising from the alternating current power supply.

The invention resides in the various constructional details by which the above object is accomplished.

For a more detailed understanding of the invention, reference is made to the accompanying drawing in which:

Figure 1 is a front elevational view of the in1- proved transformer relay with the armature thereof in its normal deenergized position;

Figure 2 is a front elevational view of the relay with the switch removed to more clearly show other elements of the relay and with the relay armature shown in its energized position; and

Figure 3 is a perspective view of the relay armature and the switch positioned thereby.

Referring to Figure 1 of the drawing, the transformer relay of the present invention broadly comprises a primary winding H and a secondary winding l2, the two windings being located upon a core iii in the form of a rectangular frame. Pivotally secured to the frame is an armature generally indicated by the reference numeral 55 and this armature carries a mercury switch iii. The winding H is maintained permanently energized and the circuit of secondary winding is opened or closed, depending upon the desired position of armature IS. The armature H3 is shown in Figure 1 in the position assumed when the circuit of secondary I2 is open and is shown in Figure 2 in the position occupied when the circuit of secondary I 2 is closed. Legends have been applied to the primary and secondary windings to enable them to be more readily distinguished from an inspection of the drawing.

The core I 3, as shown in the drawing, comprises a plurality of laminated bars secured together in rectangular formation. The four legs of the rectangular core frame are designated by the reference numerals l8, i9, 20, and M, the legs l8 and 20 being relatively long as compared to the legs l9 and 2|. The primary coil H is disposed around the longer leg 20 and the secondary coil I2 is disposed around the shorter leg 2! and at right angles to the primary coil II. It will be noted that by reason of the way in which transformer windings H and 42 are disposed the space between the legs of the transformer frame is almost entirely filled. The various laminations of the transformer are held together by rivets 25. The transformer frame i3 can if desired be secured to any suitable base (not shown) by screws 25 extending therethrough.

The armature i is formed of a pair of generally U-shaped members 26 and 2'! of magnetic material. The bases of these two members are held in close engagement with each other by any suitable fastening means. The upper ends of the members 26 and 2'! are formed so as to provide one element of a pivotal connection. It will be noted that the member 2'! has its upper end formed in an arcuate fashion and the end of member 26 extends adjacent to this arcuate portion. The armature is pivotally held in position within an extension of the leg 20 by means of a pivot pin 38.

The lower ends of the U-shaped members 26 and 2i are spread slightly apart so as to permit shading rings 32 to be placed over the lower end of member 2?. By the use of the two members 26 and 2i, it is unnecessary to slot the lower end of the armature to accommodate this shading means, as is usually necessary.

Secured to the armature assembly I5 is an L- shaped bracket 34 and an arm 35. The bracket 34 and the arm 35 are heldin position by a screw 36. The mercury switch 56 is secured to the arm 35. This switch, as is conventional, comprises a sealed envelope enclosing a pair of electrodes 39 and 4B. Also located within the envelope is a pool 38 of mercury. The mercury 38, when the switch 56 is tilted in the position shown, is disposed away from the electrodes. Upon the switch 96 being tilted to horizontal position however, the mercury is moved into bridging engagement with the electrodes, as is conventional. The mercury 38 within the switch H5 is relatively heavy due to the high density of mercury. The switch IE, it will be noted, is disposed on the right-hand side of the pivot 30 so that the mercury 38 is effective to bias the armature E5 to its open position, as shown in Figure 1. In order to insure, however, that the armature will always move to its deenergized position, it is necessary to further provide a weight 42 as a biasing means. The weight 2 is secured to the left-hand end of arm 35 by means of a screw 43. Therelay arm I5 is thus biased to its deenergized position by the combined action of weight 42 and switch IS.

The L-shaped bracket 34 is provided with a ture.

horizontal arm 45, the left-hand end of which abuts against the right-hand end of leg 20 of the core. The bracket 34 thus serves to limit the movement of the armature when tilted counterclockwise by the biasing action of weight 42 and switch I6.

Operation As previously noted, the primary winding I I is normally constantly energized. The circuit of secondary winding I2 is normally open and the parts are in .the relative positions shown in Figure 1. As long as the secondary winding I2 is thus open, the flux generated in winding I I flows through the leg 2| since this is the path of least resistance for the fiux. When it is desired to move the switch I6 to the closed position, the circuit of secondary I2 is closed, either shortcircuiting or substantially short-circuiting this winding. When this happens, the reluctance of leg 2I is enormously increased so that the flux tends to be forced through the armature I5 and the air gap between the lower end of the arma- The armature I5 is thereupon rotatedin a clockwise direction against the combined action of weight 42 and switch I5. This results in clockwise rotation of switch I6 to its closed position in which the mercury 38 bridges the electrodes 39 and 40. The armature is held in the switch closed position with a negligible amount of hum due to the shading rings 32.

By designing secondary I2 so as to produce a relatively low voltage, it is possible to use low voltage switches in the control of the circuit of the secondary winding I2. The secondary winding I2 may also, if desired, be used to energize other devices such as an electrical heating resistance. The relay transformer thus combines the functions of a step-down transformer and a relay. By reason of the extremely compact disposition of the windings by the manner in which the armature closely encircles the secondary winding, the unit occupies less space than the ordinary transformer.

Without further elaboration, the foregoing will so fully explain the gist of my invention that others may, by applying current knowledge, readily adapt the same for use under varying conditions of service, without eliminating certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured to me by the following claims.

I claim as my invention:

1. A transformer type electromagnetic actuator comprising; a core member forming a rectangular frame composed of two cross legs and two side legs; a winding upon one of said cross legs and a winding upon one of said side legs; an armature pivotally secured to said frame, said armature comprising a pair of U-shaped members fastened together adjacent their mid point and of a configuration to extend closely around one of said core windings, said U-shaped members being shaped at one end to form an element of a hinge connection with said frame while being spread apart at the other end of said armature and dis-' posed so as to be movable into engagement with said frame, a shading ring secured over one of said U-shaped members at the end at which they are spread apart, means for biasing the armature to normally maintain an air gap between the end carrying the shading ring and said rectangular frame, the said armature being actuated to form a magnetic shunt around a portion of the core when both of said windings are energized.

2. In a transformer relay; a core member having twocross legs and two side legs, said legs being disposed perpendicularly to one another to form a rectangular frame; alow voltage control secondary winding upon one of said cross legs; a high voltage primary winding upon one of said side legs; an armature pivotally secured to said frame, said armature comprising a pair of U- shaped members fastened together adjacent their mid point and of a configuration to closely extend around said secondary windings, said U- shaped members being shaped at one end to form an element of a hinge connection with said frame and being spread apart at the other end of the armature and disposed so as to be movable into engagement with said frame so that said armature forms a magnetic shunt around that portion of the core on which said secondary winding is located when actuated under control of said secondary winding; a shading ring secured over one of said armature members at the end at which said members are spread apart; a mercury switch secured to said armature and operated thereby; and means including said mercury switch and a counterweight secured at a point intermediate the pivot and movable end of said armature for biasing said armature so that the end carrying the shading ring is normally spaced from said rectangular frame to provide an air gap inthe 

